BRCGS Clause 4.16 - Reefer Trailer Inspections

I am looking for feedback on the topic of the inspection and acceptance of reefer trailers.  4.16 does not directly state that the trailer must be water tight and the interpretation guide doesn't state this either.  However, it is common practice to ensure the seals on any trailer are in good condition.  Reefer trailers have 4 holes in the floor, one on each corner for drainage.  Is it a common practice for the holes to be left unplugged during shipping regardless of the food that is being shipped.

Reasoning is that its kind of a double standard to ensure that the trailer seals on the doors are tight, no holes in the ceiling, etc...But then there are 4 holes that are open and could allow insects, mice, etc., to enter into the trailer.

Thanks for the discussion and insight.

Greetings,

Aren't the holes protected somehow? I mean there should be at least a mesh or something similar to deny access to insects/ mice etc. Leaving it just wide open doesn't sound right, while a mesh with small diameter holes will allow drainage but not the above mentioned from entering.

Regards!